Improvement in saw-mills



1. BROWN.

Saw-Mills.

Patented July 21,1874.

"UNITED STATES PATENT OFFICE.

JOSHUA BROWN, OF AU SABLE, MICHIGAN.

IMPROVEMENT IN SAW-MILLS.

Specification forming part of Letters Patent No. 153,313, dated July 21,1874 application filed May 14, 1874.

To all whom it may concern:

Be it known that I, JOSHUA BROWN, of Au Sable, in the county of Ioscoand State of hlichigan, have invented a new and useful Improvement inSaw-Mills, of which the following is a specification:

In operating gang-mills, it is customary to use heavy iron rolls, soarranged as to ride on top of the cant to keep it from being lifted inthe upstroke of the sash. To lift these rolls various modifications andcombinations of the screw and lever are employed, some of which areactuated by hand, and others by the machinery of the mill; but all ofthem are expensive in construction and slow in operation.

My invention has for its object to provide a simple, cheap, andeffective means to raise and lower the press-rolls quickly; and to thisend I place on the top girts of the gang-frame a pair of verticalcylinders, connected by a pipe at the bottom of each with the boilers ofthe mill below the water-line, or with the heater or feed-pipe betweenthe boiler or source of supply (under pressure) and the cylinder. Thepiston of each cylinder has attached to the lower end of its rod theyoke of a pressroll, so that, if water under boiler-pressure be admittedto the cylinder, the piston will be forced to the top, and thus raisethe pressroll, which may be kept there. To lower it, the cock isarranged to discharge the water from the cylinder and shut offcommunication with the source of supply.

In the drawing, A represents the frame of an iron-frame gang-mill, thesides of which are connected at the top by the girts a a. B is one ofthe t'eed-rolls, and (l a press-roll, journaled at each end in a yoke,D, which slides in the vertical guides b in the sides of the frame. E isa cylinder, mounted on each girt a, and fitted with a piston, to whichis attached the upper end of the piston-rod G, from whose lower end theyoke D is suspended. A pipe connects each cylinder with the feedpipe,heater, or boilers of the mill--below the water-line of the latter,howeverwith an ordinary three-way cock in the pipe within easy reach ofthe sawyer, who can turn its plug so as to admit water underboiler-pressure to raise the piston and its pendent press-roll, or to soturn it as to shut off communication with the source of supply anddischarge the water, when the press-roll and its attachments willdescend of their own weight.

Steam might be used in place of water under pressure, as I am wellaware; but, owing to condensation, which must necessarily result in theconnecting-pipes, and for other obvious reasons, water under pressure ispreferable.

The pipes and cooks may be arranged to exert the pressure of the wateron the upper sides of the pistons, if the weight of the pressrolls beinsufiicient for the purpose.

What I claim as my invention, and desire to secure by Letters Patent, is

The cylinder E, mounted on a gangframe, and having the yoke D of thepress-roll O suspended iroin the rod G of its piston, the same beingarranged to raise its attachments by steam or water entering saidcylinder under pressure, substantially as described.

JOS HUA BROVN.

Witnesses:

JonN HURS'I, HUGH BUYERs.

